With the development of communication technologies, operators are more and more eager to develop Internet services. However, because the Packet Switched (PS) network architecture of Wideband Code Division Multiple Access (WCDMA) basically inherits the General Packet Radio Service (GPRS), the cost per megabyte cannot be reduced quickly even after the High-Speed Packet Access (HSPA) on air interface is deployed.
The 3rd Generation Partnership Project (3GPP) proposes a One Tunnel solution for the PS network architecture in Release 7 (R7). As shown in FIG. 1, this network architecture includes the following network elements:
NodeB 101;
Mobile backhaul 102;
Radio Network Controller (RNC) 103;
Serving GPRS Support Node (SGSN) 104;
Internet Protocol (IP) backbone 105;
Gateway GPRS Support Node (GGSN) 106; and
Public Data Network (PDN) 107.
The NodeB 101 is interconnected with the RNC 103 through an Iub interface over a mobile Iub transport network. The RNC 103 is interconnected with the SGSN 104 through an IuPS interface. The SGSN 104 is interconnected with the GGSN 106 through a Gn/Gc interface over the IP backbone 105. The GGSN 106 is interconnected with the PDN 107 through a Gi interface.
The basic principle of the One Tunnel solution is to let the control plane signaling go along the conventional path from the RNC 103 through the SGSN 104 to the GGSN 106, the User Plane (UP) data flow does not pass through the SGSN 104, and the RNC 103 is directly connected to the GGSN 106 through the Gn UP interface, so that the SGSN 104 is no longer a capacity bottleneck. However, in the One Tunnel solution, the PDN is still connected over the GGSN of the backbone network and therefore the efficiency of PS service transmission is low.